1. Field of the Invention
The invention relates to a process for cutting through a material web running into a driven winding roll and for the fastening of the start of the following web on a winding core or a winding tube in which the web is guided into the winding roll via a guide device consisting preferably of a winding roller and after being cut through is laid around the winding tube in a guide channel. The present invention also relates to an apparatus for carrying out this process.
2. Description of the Related Art
Continuously produced material webs, e.g., single-layer webs of thermoplastic plastic or flat hose webs made in a blown foil facility, must be wound into winding rolls for storage and handling. In so doing, the current web running continuously into a winding roll must be cut through after the completed winding of a winding roll and the start of the following web must be fastened for initial winding onto a winding core or a winding tube in order to be able to continue the winding process of the continuously fed web without disturbance or redirection.
It is a known practice to wind the start of a web to be wound into a winding roll onto a winding tube which is provided with an adhesive coat for fastening the start of the web.
In order to avoid this adhesive coat to be applied with an additional expense, apparatuses for the adhesive-free initial winding of webs onto winding tubes are also known. A known apparatus for the adhesive-free initial winding of a start of a web onto a winding core or winding tube consists of a winding tube positioned on a guide roller provided with vacuum holes in its casing, onto which winding tube, after cutting through the web, the start of the web formed thereby is wound due to the fact that a suction box is run into the roller gap between the guide roller and the winding tube, said suction box being provided on an elongated edge with a knife cutting through the web and adjacent to the knife with a wall curved in the form of a shell, said wall forming, with an area of the circumferential surface of the winding tube, a channel curved in the form of a shell, where on the front end of said channel, in the area of the roller gap, air is suctioned through the suction box in such a manner that the start of the web is suctioned into the guide channel and thereby is held fast on the winding tube, that the start of the web runs into the gap between the guide roller and the winding tube in which it is covered by the following web so that the start of the web is held fast on the winding tube after one winding.
A particular problem in the initial winding of winding cores or winding tubes with a start of a web consists, however, of the fact that the webs to be wound into winding rolls are asymmetric, which means, that they have sides with different properties. According to the further processing of the webs to be wound into winding rolls, it is thus desired that one or the other side lies on the outside of the winding roll. In order to be able to produce winding rolls on which the webs are wound with alternating outer sides, therefore one time with one side lying outside and another time with the other side lying outside, it is necessary to drive the guide roller and the winding core or the winding tube in opposite directions of rotation, which makes it necessary to feed the start of the web formed by separation of the web from the guide roller to the winding tube, according to the direction of rotation, from directions opposite to one another. A feed of this type of the start of the web to the winding tube from directions opposite to one another is not possible in the known apparatus.